Instruments: Allocation shows different results on iOS 17

Hey, I'm learning Instruments (Xcode 15.1), and I've encountered a situation for which I haven't found an answer yet. I have an application that loads 12 large images, with the last one taking the most space at 147MB.

Instruments on the iOS 15 simulator correctly shows 21 allocations, as in the example from the book, because the last image is split into smaller parts due to poor optimization.

But if I run the same example on the iOS 17 simulator, I have even fewer allocations than loaded images.

And my question is whether memory allocation for large images is handled differently in iOS 17, or where can I read more about it?